<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>提示框</title>
</head>
<style>
.tooltip {
    position: relative;
    display: inline-block;
    border-bottom: 1px dotted black;
}

.tooltip .tooltiptext {
    visibility: hidden;
    width: 120px;
    background-color: black;
    color: #fff;
    text-align: center;
    border-radius: 6px;
    padding: 5px 0;
    position: absolute;
    z-index: 1;
    top: -5px;
    right: 110%;
}

.tooltip .tooltiptext::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 100%;
    margin-top: -5px;
    border-width: 5px;
    border-style: solid;
    border-color: transparent transparent transparent black;
}
.tooltip:hover .tooltiptext {
    visibility: visible;
}
</style>
<body style="text-align:center;">

<h2>左侧提示框/右侧箭头</h2>

<div class="tooltip">鼠标移动到我这
  <span class="tooltiptext">提示文本</span>
</div>

</body>
</html>